Quick-action fasteners

ABSTRACT

Quick action fasteners, nuts, and end-to-end couplers, which eliminate the need for time-consuming and labor-intensive threading of nuts, couplers, and the like to helically threaded reinforcing rod and sections thereof and to other types of textured surface reinforcing rod, particularly in environments in which the fastener will be subjected to high loads and/or torques. Fasteners according to the invention include a housing, a plurality of nut segments, and an end cap for retaining the nut segments in a specially shaped bore defined in the housing. The bore includes a tapered section and an expansion section; the nut segments are formed, along interior segment surfaces, to be closely engageable to a corresponding section of the reinforcing rod. The nut segments are also shaped, along their exterior surfaces, to be congruent with tapered section of the bore. The nut segments are movable from locked engagement with the tapered section and the rod section to a release position in which the nut segments can be moved into the expansion section to slide or &#34;ratchet&#34; over the surface of the rod.

BACKGROUND OF THE INVENTION

This is a continuation-in-part of application Ser. No. 830,295, filedFeb. 14, 1986, now abandoned.

This invention relates to quick-action nuts, fasteners and couplers and,more particularly, to anchor nuts and couplers for fastening reinforcingrod, especially in environments in which high loads and/or torques areapplied to nuts, fasteners, and couplers.

In many applications of reinforcing rod, commonly referred to as"rebar," it is desirable to have available accessories, such as nuts andcouplers, with which reinforcing rods can be fastened together or toother structures. For example, reinforcing rod is often used in tunnelwall, mine, and slope stabilization and/or soil anchoring systems. Thereinforcing rod is inserted and/or grouted into the rock or soil to bestabilized; an anchor plate or bearing plate is then fitted around theprojecting reinforcing rod and placed against the slope or wall to bestabilized and held in position with, for example, a clamp applied tothe projecting end of the reinforcing rod. While such systems areeffective, their assembly is difficult due to the heavy reverse loadingof the clamps, and is extremely labor intensive.

Some of these difficulties may be reduced through the employment ofhelically threaded reinforcing rod systems which include large, threaded"nuts" that may be screwed on to the ends of the reinforcing rod and,for example, tightened against the anchor plates. Helically threadedreinforcing rods and systems are disclosed, for example, byFinsterwalder, U.S. Pat. No. 3,292,337; Finsterwalder, et al., U.S.Pat.No. 3,561,185; and Tani, U.S. Pat. No. 4,056,911. Although suchsystems have greatly increased the number of applications of reinforcingrod, known nuts for use with helically threaded reinforcing rodgenerally have the disadvantage of requiring a great many revolutions atthe nut or other fastener on the reinforcing rod before the fastener isbrought into the desired, locked position on the threaded reinforcingrod. Such processes can be time consuming and inefficient.

Quick-action fasteners for screws and bolts are known See, e.g., Okada,U.S. Pat. No. 4,083,393; Fullerton, U.S. Pat. No. 4,378,l87; Beswick,Great Britain Pat. No. 590,430; Schertz, U.S. Pat. No. 3,352,341;Jansen, U.S. Pat. No. 2,896,496; Desbrueres, U.S. Pat. No. 2,021,051;and Norwegian Pat. No. 72,788. Heretofore known quick-action fastenershave been designed for and intended for use with relatively light-dutyscrews, bolts, and the like, and fail under the loading required forsuccessful use in such high load and/or high torque environments such asthose encountered in applications of reinforcing rod systems. Such knownfasteners are adapted exclusively for use with helically threaded shaftsand for convenient removal therefrom by a quick release mechanism or by"unscrewing." In addition, the complexity and hence manufacturing costsof known quick-action fasteners are typically quite high.

A second application in which reinforcing rods are desirably coupledtogether or those in which long links of reinforcing rods are necessaryas, for example, large prestressed concrete platforms, walls, and thelike. Since it is generally inconvenient to manufacture, ship, and/orassemble arbitrarily long lengths of reinforcing rod, it is necessarythat shorter links of reinforcing rod be coupled end-to-end. The ends ofthe reinforcing rods may be wired together, welded together (seeGelfand, U.S. Pat. No. 3,554,270) or clamped together (see Gelfand, U.S.Pat. No. 3,694,012 and Miles, U.S. Pat. No. 4,362,423). In addition,reinforcing rods which are helically threaded over their entire lengthsor over relatively short end sections may be screwed together with anappropriate fitting. See, e.g., Majewski, U.S. Pat. No. 3,782,839. Eachof these known systems for coupling reinforcing rods end-to-end arelabor intensive, requiring considerable manual effort to assemble, andfrequently require specially manufactured, machined and/or threadedreinforcing rod. These disadvantages are particularly acute when it isdesired to couple reinforcing rods end-to-end in a vertical orientation;the clamping, screwing, or other assembly operations may then have to beperformed relatively high in the air. Also, the complexity and hencemanufacturing costs of such systems are typically high.

SUMMARY OF THE INVENTION

Quick action fasteners are provided which eliminate the need fortime-consuming and labor-intensive threading of nuts, couplers, and thelike to helically threaded portions of reinforcing rod and greatlyreduce the difficulty and inefficiency of clamping and couplingtextured-surface reinforcing rod. The fasteners of the invention arerelatively simple to manufacture and use and withstand typical loadingforces of 120 tons or more.

Fasteners according to one embodiment of the invention include ahousing, a plurality of nut segments, and an end cap for retaining thenut segments in a specially shaped bore defined in the housing. The boreincludes a tapered section and an expansion section; the nut segmentsare formed, along interior segment surfaces, to be closely engageable toa section of a textured surface reinforcing rod or bolt. The nutsegments are also shaped along their exterior surfaces to be congruentwith the tapered section of the bore. The nut segments are movable fromlocked engagement with the tapered section and the rod or bolt sectionto a release position in which the nut segments can be moved into theexpansion section to slide or "ratchet" over the surface indentationsand projections of the rod or bolt.

An important feature of the fasteners according to the invention is theangle, with respect to the axis of the bore, of the taper of the taperedsection and the corresponding, matching angle of tapered portions of thenut segments. The proper choice of this angle, about 9° in the preferredembodiments, enables the use of the fasteners in high-load and torqueenvironments by ensuring even distribution of the load over the interiornut segment surfaces and, hence, the threaded rod.

Fasteners according to the invention also include limit means to preventmisalignment of the nut segments along the length of the rod. Postprojecting into the expansion section into corresponding slots in thenut segments may be used as limit means; alternatively, or incombination therewith, an end cap mounted to one end of the housing maybe used to limit the travel of the nut segments in the bore. Inembodiments adapted for use with helically threaded reinforcing rod, theprojection of the posts into the corresponding slots serve to allowthese fasteners to be "unscrewed" from the helically threaded rod.

In a second embodiment of the invention, particularly adapted to couplereinforcing rod sections end-to-end includes a housing having athrough-going bore which includes a pair of generally thrust or conicaltapered sections and a pair of cylindrical expansion sections, acylindrically section being adjacent or corresponding tapered section,tapered sections being generally located at opposite ends of the bore.The second embodiment according to the invention also includes a pair ofpluralities of arcuate nut segments, each plurality of nut segmentsbeing mounted in a corresponding end of the bore to be disposable aboutan end section of one of the reinforcing rods. Each nut segment has aninterior segment surface formed to define a textured surfacecomplimentary to a corresponding portion of the textured surface of thereinforcing rod, and an exterior segment surface including a taperedportion formed to be congruent with a corresponding portion of thetapered sections of the bore. The second embodiment according to theinvention also includes stops for limiting the movement of eachplurality of nut segments along the bore axis. The stops may be postsprojecting into each expansion section into corresponding slots in eachof the pluralities of nut segments. Alternatively, or in addition, thetravel of each of the pluralities of pairs of nut segments may belimited with a plate or other structure inserted through the housingbetween the pluralities of nut segments

In each embodiment according to the invention, the interior surfaces ofthe nut segments can be formed to be complimentary to the texturedsurface of any reinforcing rod desired to be used. The interior nutsegment surfaces may be formed to have helical threads for use withhelically threaded reinforcing rod. However, the invention is not solimited, and may be adapted for use with other reinforcing rod systemshaving a variety of surface ribs, indentations, protrusions, and thelike.

Other features and advantages of fasteners according to the inventionwill become apparent from the detailed description of the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic, partially cut away representation of a typicalreinforcing rod application of a type with which the present inventionis intended to be used.

FIG. 2 is an exploded perspective view of one embodiment of theinvention, indicating two of the nut segments in phantom.

FIG. 3 is a cross-sectional view of the first embodiment of theinvention, taken generally along section 3--3 of FIG. 2 and showing thenut segments in a lock position.

FIG. 4 is a cross-sectional view of the first embodiment of theinvention, taken generally along section 3--3 of FIG. 2 and showing thenut segments in a release position.

FIG. 5 is a cross-sectional view of a modification of the firstembodiment of the invention taken generally normal to the bore axis.

FIG. 6 is a cross-sectional view of a second embodiment of takengenerally normal to the bore axis.

DETAILED DESCRIPTION OF THE SPECIFIC EMBODIMENT

A typical system 10 of a type with which the present invention may beused is shown schematically in FIG. 1. System 10 includes a reinforcingrod 12, an anchor plate 14 and a helically threaded anchor nut 16. Thesystem 10 shown in FIG. 1 is intended for use with grouting concrete,etc. in the region numbered 18, for reinforcing rock or dirt slopes andwalls. Such systems 10 typically may also provide for the use of variousbearing plates, washers, couplers (for splicing reinforcing rodsend-to-end, e.g.), and the like.

One quick-action fastener 20 according to the invention, shown asadapted for use in a reinforcing rod system such as system 10, is shownin exploded perspective view in FIG. 2, and in cross-section in FIGS. 3and 4. Fastener 20 generally includes a housing 22, a plurality of nutsegments 24, an end cap 26, and a snap ring 28.

Housing 22 includes, along a bore axis 30, a throughgoing bore 32.Throughgoing bore 32 in housing 22 includes a tapered section 34 and anexpansion section 36. Tapered section 34 has a generally frustoconicalshape narrowing in a direction along bore axis 30 opposite the directionof the primary load on fastener 20 (the "forward direction" 37).Expansion section 36 is conveniently made cylindrical with a diameter atleast as large as and preferably larger than, the largest diameter oftapered section 34. The precise dimensions and shape of expansionsection 36 will be dependent upon the corresponding dimensions of nutsegments 24 and other factors to be discussed below. Housing 22 isprovided with a plurality of posts 38 projecting, in the preferredembodiment, inwardly of expansion section 36.

In fastener 20, housing 22 is provided with a pilot flange 30 at oneend; typically, pilot flange 40 is frustoconical in shape having a taperin a direction opposite of that of tapered section 34, and serves thefunction of guiding the insertion of a reinforcing rod into bore 32.

The exterior surface of housing 22 may be formed to have a variety ofshapes, depending upon the particular purpose for which a particularfastener 20 is intended. In the embodiment shown in FIGS. 2-4, housing22 includes a generally spherical anchor section 42 for matinglyengaging with a corresponding anchor plate, e.g., anchor plate 14 ofFIG. 1. Housing 22 also includes, in the preferred embodiment, aplurality of tool engagement surfaces 44; in the embodiment shown inFIGS. 2-4, tool engagement surfaces 44 comprise opposing pairs ofmutually parallel flat surfaces for engagement of, e.g., a wrench, withfastener 20.

Nut segments 24 are typically arcuate as shown in FIG. 2 and include, onthe sides of nut segments 24 adjacent bore axis 30, interior segmentsurfaces 50 and, distal bore axis 30, exterior segments surfaces 52.Interior segment surfaces 50 are formed to have textured surfaces 54 tobe complimentary to, and matingly engageable with the correspondingsurface texture of the particular type of reinforcing rod, e.g.,reinforcing rod 12 of FIG. 1. Exterior segment surfaces 52 includetapered portions 56 and upper portions 58. Tapered portions 56 will becongruent to a corresponding portion of tapered section 34; preferably,the length of tapered portions 56 along bore axis 30 will be somewhatless than the corresponding length of tapered section 34 such that, whennut segments 24 are mutually aligned against tapered section 34, theextension of nut segments 24 in forward direction 37 is somewhat lessthan that of tapered section 34, as shown most clearly in FIG. 3. Such achoice is preferred to prevent possible inward distortion of the lowerends of nut segments 24 toward the reinforcing rod which would therebyweaken fastener 20 and hence its engagement to the reinforcing rod, andalso tend to cut into and thereby weaken the reinforcing rod.Preferably, nut segments 24 are formed to extend, in forward direction37, about 0.018 inches or more less than tapered section 34, so thatunder a typical load of about 120 tons or more, nut segments 24 are notforced beyond tapered section 34 in forward direction 37.

Textured surfaces 54 of the individual nut segments 24 will generally besomewhat different but will be chosen to form, when nut segments 24 aremutually aligned in contact, indentations and protrusions generallycorresponding to those of a corresponding section of the reinforcingrod.

In some embodiments, nut segments 24 will be formed to have, in upperportions 58, a plurality of slots 60. Slots 60 will be orientedgenerally axially, approximately parallel to bore axis 30, andpositioned to engage with corresponding posts 38. The lengths of slots60 will be chosen such that the ends of slots 60 adjacent taperedportions 56 engage posts 38 to limit the motion of nut segments 24 alongbore axis 30 in a direction away from tapered section 34, in a "reversedirection" 61.

End cap 26 serves to retain nut segments 24 within bore 32 and includesa rod insertion hole 62 for limiting, in some embodiments, the movementof nut segments 24 along bore axis 30. End cap 26 is fixedly engageableto housing 22 in any of a variety of ways. In the embodiment shown inFIGS. 2-4, end cap 26 is formed to mate with a corresponding ledge 66formed in one end of bore 32 of housing 22. In this embodiment, end cap26 is retained against ledge 66 with a snap ring 28 which is engageableto a corresponding snap ring groove 68 in housing 22.

Nut segments 24 are formed, in cooperation with bore 32, to be freelymovable between a locked position shown in FIG. 3 to a release positionshown in FIG. 4. In the locked position, tapered portions 56 engagetapered section 34 and nut segments 24 are mutually aligned along boreaxis 30 to closely circumscribe a reinforcing rod section (not shown inFIGS. 3 and 4). In the locked position, nut segments 24 mutually engageunder a typical load in reverse direction 61 of about 120 tons toclosely encircle the threaded rod section to within a clearance of lessthan about 1/32 of an inch (less than 1 mm). When the load is applied tofastener 20 generally along bore axis 30 in reverse direction 61, nutsegments 24 cooperate with tapered section 34 of housing 22 to preventmovement of fastener 20 in reverse direction 61 and fixedly grasp thereinforcing rod.

In the release position, shown in FIG. 4, nut segments 24 are disengagedfrom tapered section 34 toward reverse direction 61 into expansionsection 36. The allowed travel 73 of nut segments 24 within bore 32 intoexpansion section 36 along bore axis 30 is, in the embodiment shown inFIG. 4, limited both by the engagement of posts 38 with thecorresponding ends of slots 60 and by the engagement of nut segments 24with lower surface 64. In alternate embodiments, the limit of travel 73of nut segments 24 could be defined either by the engagement of posts 38with the ends of slots 60 or by the engagement of nut segments 24 withlower surface 64. The dimensions, e.g., travel 73, of expansion section36 are chosen to allow sufficient upward travel of nut segments 24within bore 32 to disengage tapered portions 56 from tapered section 34and to allow radial movement of individual nut segments 24 away frombore axis 30, thus allowing the reinforcing rod to slip through bore 32.The dimension of expansion section 36 along bore axis 30 is notcritical; however, travel 73 of nut segments 24 within bore 32 towardend cap 26, must be sufficiently small that the possibility of mutualmisalignment of nut segments 24 along bore axis 30 is eliminated. If,e.g., one of nut segments 24 were separated, in the locked position,from the remaining nut segments 24 along bore axis 30 by a significantdistance, the load on fastener 20 in the locked position would beunevenly applied to the threaded rod, risking failure of fastener 20.For example, in FIG. 3, interior segment surfaces 50 are shown to becomplimentary to the exterior surface of a helically threadedreinforcing rod. Interior segment surfaces 50 are thus formed to havehelical indentations with a pitch 70 and a thread height 72substantially equal to the corresponding pitch in thread height of thehelically threaded reinforcing rod to be used. In such an embodiment ofthe invention, the stops limit travel 73 of nut segments 24 to an amountless than pitch 70 and thus maintain the mutual alignment of nutsegments 24. The "stop" function is performed, in the embodiment shownin FIG. 3 by the engagement of posts 38 with the ends of slots 60 and/orthe location of lower surface 64. In alternate embodiments havingdifferently formed interior segment surfaces 50 for use with other typesof textured reinforcing rod, analogous considerations will govern thedistance over which nut segments 24 are allowed to travel.

Tapered section 34 and tapered portions 56 of nut segment 24 are eachaligned, with respect to bore axis 30, by a taper angle 76; taper angle76 is critical in high load and/or torque applications. Under typicalloads in reverse direction 61 ("reverse loads") encountered with the useof fastener 20 with helically threaded rods of 120 tons or more, iftaper angle 76 is too large (greater than about 15°), the load will notbe distributed evenly over the length of interior segment surfaces 50,but will be concentrated in the region of tapered portions 56. This maylead to over-compression of the reinforcing rod in this region and/orfailure of fastener 20 under typical reverse loads. Similarly, if taperangle 76 is chosen to be too small (less than about 6°) the loading offastener 20 will again be concentrated in the region of tapered portions56 and upper portions 58 will tend to "bow" away from bore axis 30,again leading to failure of fastener 20. Satisfactory distribution ofthe reverse load along the length of nut segments 24 is obtained with ataper angle 76 in the range of about 7° to about 12°. Preferably, taperangle 76 is about 9° for a threaded rod diameter of about 1.5 in., alength of taper portions 56 of about 1.5 in., and a total nut segmentlength (along bore axis 30) of about 2.5 in.

In some embodiments, it is convenient to include an o-ring 78 or othersuitable elastic expansion means around nut segments 24 to provide asmall bias of nut segments 24 inward from their respective releasepositions to the mutually aligned lock positions. Such an o-ring 78 willbe mounted in a suitable groove inscribed in exterior segment surfaces52. O-ring 78 will be resilient, but sufficiently expansible to allownut segments to readily move radially outward into expansion section 36.

In those embodiments of the invention for use with helically threadedreinforcing rod, posts 38, by their engagement with slots 60, also serveto allow fastener 20 to be disengaged from the threaded rod by turningfastener 20 with a tool or other wrench in a direction counter to thethread direction of the threaded rod. That is, as fastener 20 is turnedin such a manner, posts 38 engage slots 60 to transmit the force appliedto tool engagement surfaces 44 to nut segments 24, allowing thedisassembly, by "unscrewing" fastener 20 from the threaded rod.

Although the operation of fastener 20 will be apparent to those skilledin the art from the above description, the operation of fastener 20 willnow be outlined in more detail. With the reinforcing rod oriented in thedesired position and location, one end of the reinforcing rod isinserted into bore 32, in some embodiments guided with pilot flange 40.As the threaded rod is inserted into bore 32, nut segments 24 will beforced toward reverse direction 61 where nut segments 24 will be movedoutward radially by engagement with the reinforcing rod and therebyallow passage of the reinforcing rod past thread surfaces 54 of nutsegments 24. When fastener 20 is in the desired position, fastener 20 isreverse-loaded to force nut segments 24 into the locked position andthereby engage textured surfaces 54 to the desired location of thereinforcing rod. Reverse loading can be accomplished in various ways,depending on the particular application of fasteners 20. For example, insituations in which the reinforcing rod system 10 is being used toanchor soil in conjunction with, e.g., grouting or other anchoringsystems, an impact force, e.g., a hammer blow, may be applied to the endof the threaded rod to urge the reinforcing rod opposite the directionof insertion of fastener 20 and thereby force, e.g., anchor section 42,against a suitable anchor plate, e.g., 14 (FIG. 1). In someapplications, such as reinforcing rod systems, the reinforcing rod willbe prestressed.

In those embodiments of the invention adapted for use with helicallythreaded reinforcing rod, fastener 20 can be turned using toolengagement surfaces 44 to fully engage fastener 20. In such embodiments,fastener 20 can be disengaged from the (threaded) reinforcing rod by"unscrewing" fastener 20 along the entire projecting length of thereinforcing rod using, e.g., tool engagement surfaces 44. In otherembodiments of the invention, it will not in general be possible toeasily remove fastener 20 from reinforcing rod having different texturedsurfaces. However, in many applications this will not be a significantdisadvantage since the positioning of fastener 20 is intended to berelatively permanent.

The orientation of the reinforcing rod is not critical to the successfuluse of the invention; if the threaded rod is oriented to extend upwardfrom e.g., a slope or wall to be reinforced, fastener 20 will typicallydrop to the desired position by its own weight under the force ofgravity. In other orientations of reinforcing rod, it may be necessaryto move fastener 20 along the length of the threaded rod by hand. Suchan operation is easily accomplished.

The material from which the components of fastener 20 are made is notcritical; however, the material must be one which is capable ofwithstanding the forces to be applied to fastener 20 without significantdistortion. One suitable material is number 4130 alloy steel.

A modification 20' of fastener 20 is shown in cross-section in FIG. 5;the view of FIG. 5 is generally perpendicular to bore axis 30. Inmodification 20', slots 60' are formed near the respective centers ofexterior segments surfaces 52', rather than, as indicated in FIG. 2, atthe extrema of exterior segment surfaces 52. In modification 20', posts38' are formed with a plurality of screws 82, e.g., set screws or thelike, mounted in threaded holes in housing 22' to extend into expansionsection 36'.

Fastener 20 can be manufactured by any number of processes known tothose skilled in the art. For example, the various parts of fastener 20could be machined, forged, cast, or the like.

Although fasteners 20, 20' shown in FIGS. 2-5 each have three nutsegments 24, other numbers of nut segments are possible; a correspondingnumber of slots 60 and posts 38 will then be used. However, the use ofthree nut segments 24 is preferred, as the distribution of the requiredreverse loads on the reinforcing rod is more easily obtained with threenut segments 24 than with, e.g., four or more nut segments 24.Similarly, while two nut segments 24 could be used in alternateembodiments of the invention, in order to provide sufficient space inexpansion section 36 for textured surfaces 54 to clear the reinforcingrod, the dimensions of expansion section 36 would be correspondinglylarger due to the greater curvature of textured surfaces 54.

A second embodiment according to the invention is shown incross-sectional view in FIG. 6; this embodiment is the coupler forcoupling pairs of reinforcing rod sections together end-to-end and isgenerally denoted coupler 120. Coupler 120 includes, generally, a pairof fasteners similar to fastener 20 arranged in mutually affixedend-to-end. In FIG. 6, the elements corresponding to the pair offasteners 20 are numbered to correspond to the numbers of analogouselements of FIGS. 1 to 5, although increased by one hundred. Theportions of coupler 120 analogous to one fastener 20, in a lockposition, are indicated with unprimed numbers in FIG. 6; the elementscorresponding to the other of the fasteners 20, in a release position,are indicated with primed numbers. One arrangement for assemblingcoupler 120 and fastening the two halves of coupler 120 together is alsoindicated in FIG. 6. In this embodiment of coupler 120, housings 122,122' are provided with flanges 180, 180' extending outward thereof.After insertion of nut segments 124, 124' into the corresponding ends ofhousing 122, 122' and insertion of end caps 126, 126' flanges 180, 180'may be fixedly connected as with bolts or other fasteners or by welding.Alternatively, housings 122, 122' could be formed in a single unitarypiece. To prevent excessive travel of nut segments 124, 124', a stopsuch as bolts or one or more plates 126, 126', for example, could beinserted through appropriately positioned holes in or welded to housing122, 122', to separate the two pluralities of nut segments formaintaining the pluralities of nut segments 124, 124' in theirappropriate locations. Such bolts or plates 126, 126', could have theadditional advantage of then preventing passage of one end of onereinforcing rod into the portion of bore 132 intended for the end of theother pair of reinforcing rods.

One end of each of the pair of reinforcing rods could be inserted intoone corresponding end of coupler 120, where the reinforcing rods wouldthen be held in the desired positions prior to, for example, reverseloading of the coupler 120 or embedding of the reinforcing rods, withcoupler 120, in concrete.

In addition, fasteners according to the present invention andconstructed according to similar principles could be used for couplingpairs of reinforcing rod sections together at an angle with respect toeach other.

While the above is a complete description of the preferred embodimentsin the invention, other arrangements and equivalents are possible andmay be employed without departing from the spirit and scope of theinvention. For example, other variations in the size or shape of thepresent invention will be readily apparent to those skilled in the art.The dimensions of fastener 20 may be readily changed proportionately foruse with reinforcing rods of various diameters. The materials anddimensions utilized in the preferred fastener may be varied, dependingupon manufacturing requirements and the desired characteristics of thefinished fastener. Therefore, the description and illustrations shouldnot be construed as limiting the scope of the invention, which isdelineated by the appended claims.

We claim:
 1. A quick action end-to-end fastener for coupling a pair ofreinforcing rods end-to-end, the fastener comprising:a housing defining,along a bore axis, a throughgoing bore, the bore including a pair ofgenerally frustoconical tapered sections and a pair of cylindricalexplansion sections, each cylindrical section being adjacent acorresponding tapered section, the tapered sections being generallylocated at opposing ends of the bore; a pair of pluralities of arcuatenut segments, each plurality of nut segments being mounted in the bore,adjacent an end thereof, to be disposed about an end section of one ofthe reinforcing rods, each nut segment having an interior and anexterior segment surface,the interior segment surface being formed todefine a textured surface matingly engageable to a corresponding portionof the reinforcing rod, and the exterior segment surface including atapered portion formed to have a shape congruent with a correspondingportion of the tapered sections and an upper portion; and limit meansfor limiting the movement of each plurality of nut segments along thebore axis in the direction of the corresponding expansion section;wherein each plurality of nut segments is movable between a lockingposition in which the tapered portions engage the corresponding taperedsection and the textured surfaces are engageable, over substantially thewhole thereof, to the end section of the corresponding reinforcing rodto substantially prevent movement of the fastener relative to thecorresponding reinforcing rod, and a second position in which thetapered portions are disengaged from the corresponding tapered sectionand the textured surfaces are disengageable from the end section of thecorresponding reinforcing rod to allow movement of the fastener relativeto the corresponding reinforcing rod.
 2. The fastener of claim 1 furthercomprising a plurality of axial slots defined in the nut segments;andwherein the limit means comprises a plurality of posts extending intothe expansion section from the housing, each post being engageable witha corresponding slot.
 3. The fastener of claim 1 wherein the limit meanscomprises a plate positioned interiorly of the bore between the ones ofthe pair of pluralities of nut segments.
 4. The fastener of claim 1further comprising a plate positioned interiorly of the bore between theones of the pair of pluralities of nut segments.
 5. The fastener ofclaim 1 adapted to fasten helically threaded reinforcing rods andwherein the interior segment surfaces are formed to define correspondingthread surfaces.
 6. The fastener of claim 1 wherein the tapered sectionshave surfaces inclined at a taper angle of between about 7° and about12° relative to the bore axis.
 7. The fastener of claim 6 wherein thetaper angle is about 9°.
 8. The fastener of claim 1 adapted to fastenreinforcing rods having surfaces that are textured but not helicallythreaded.